{% assign visible_chapters = site.books | where: "book", "pies" | where_exp: "item", "item.hidden != true" | sort: "order" %} {% assign nav_previous = nil %} {% assign nav_next = nil %} {% for chapter in visible_chapters %} {% if chapter.url == page.url %} {% if forloop.index0 > 0 %} {% assign prev_idx = forloop.index0 | minus: 1 %} {% assign nav_previous = visible_chapters[prev_idx] %} {% endif %} {% assign next_idx = forloop.index0 | plus: 1 %} {% assign nav_next = visible_chapters[next_idx] %} {% endif %} {% endfor %}
{% if nav_previous.url %}

{{ nav_previous.title }}

 {% else %}

-

{% endif %} {% if nav_next.url %}

{{ nav_next.title }}

 {% else %}

-

{% endif %}